Evaluation and integration of disparate classification systems for clefts of the lip.

Kathie H Wang,Craig B Birgfeld,Carrie L Heike,Raymond W Tse,James F Brinkley,Timothy C Cox,David A Fitzsimons,Jose L V Mejino,Melissa D Clarkson

doi:10.3389/fphys.2014.00163

Abstract

Orofacial clefting is a common birth defect with wide phenotypic variability. Many systems have been developed to classify cleft patterns to facilitate diagnosis, management, surgical treatment, and research. In this review, we examine the rationale for different existing classification schemes and determine their inter-relationships, as well as strengths and deficiencies for subclassification of clefts of the lip. The various systems differ in how they describe and define attributes of cleft lip (CL) phenotypes. Application and analysis of the CL classifications reveal discrepancies that may result in errors when comparing studies that use different systems. These inconsistencies in terminology, variable levels of subclassification, and ambiguity in some descriptions may confound analyses and impede further research aimed at understanding the genetics and etiology of clefts, development of effective treatment options for patients, as well as cross-institutional comparisons of outcome measures. Identification and reconciliation of discrepancies among existing systems is the first step toward creating a common standard to allow for a more explicit interpretation that will ultimately lead to a better understanding of the causes and manifestations of phenotypic variations in clefting.

Highlights

Cleft lip (CL) is one of the most recognizable anomalies and has been the focus of intense clinical and research efforts for many decades
IDENTIFICATION OF CL CLASSIFICATION SYSTEMS We focused our investigation on classification systems that included the broad definition of “cleft lip,” that is, those involving structures anterior to the incisive foramen only
To identify the different CL classification systems, we started with the systems utilized in our centers and others familiar to us based on our knowledge and expertise in the field, and supplemented this by performing a PubMed search to identify additional systems using combinations of the following terms: orofacial cleft, CL, unilateral, bilateral, classification, description, systems, and phenotype

Summary

Introduction

Cleft lip (CL) is one of the most recognizable anomalies and has been the focus of intense clinical and research efforts for many decades. Pediatricians, surgeons, speech pathologists, nutritionists, geneticists, and developmental biologists often interpret the term “cleft lip” differently. Much of this undocumented confusion resides in the differing level of granularity with which each person considers the disorder. The term “cleft lip” could refer to variable combinations of defects involving the upper lip, the anterior segment of the maxillary alveolar ridge, and/or the portion of the hard palate anterior to the incisive foramen, that is, any phenotype having an embryologic basis as a perturbation of the growth and/or fusion of the medial nasal process with the paired maxillary and lateral nasal processes

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